Process for treating alumino-silicates



Patented Jan. 19, 1926;

UNITED STATES ATENT oFFlcE.

' HERMANRIEINBOLD .AN D HUGO REINZBOLD, OI OMAHA, NEBRASKAt SAID HUGOBEEN BOLD ASSIGNOR T0 SAID HERMAN REINBOLD.

' rnoonss FOR TREATING ALumINo-sILIcArns.

No Drawing.

7 '0 all whom it may camera:

Be it known that we, HERMAN REINBOLD and HUGO REINBOLD, both citizens ofthe United States of America. residing at Omaha, in the county ofDouglas and State of Nebraska, have invented certain new and usefulImprovements in Processes for Treating Alumino-Sili'cates, of which thefollowing isa specification.

This invention relates to processes for preparing-minerals such as trueor altered bentonites' or other alumino-silicates, for use as a watersoftening agent.

In their natural state the clays or minerals (hydrous aluminumsilicates) are deficient in' either or both alumina or alkali, owing toinfiltration or alteration by lime, magnesia, iron, etc and'since theseimpurities have no beneficial effect when the mineral is used for watersoftening purposes they impair the ef ficiency of the mineral by theamount or active' ingredients (alumina and sodium) which they havereplaced. a.

The principal object of this invention is toprov-ide a process or meanswhereby the altered mineral, as found in nature (originally a truealuminum sodium silicate having a definite structural formula), can bereconverted or reconstructed to its original pure state by removing theundesirable constituents, lime and magnesia, etc., as chlorides andsulphates and substituting for them, aluminum and sodium hydroxidesthealuminum and sodium hydroxides being placed in actual chemicalcombination in the mineral fOIIIllIW' a ure stable sodium aluminums1l1cate.

It is not new to remove infiltrated impuri ties, such as calcium,magnesium, iron, etc., by'contact with a sodium chloride solution but tocarry this process further and replace the removed impurities byaluminum and sodium hydroxides so as to restore the structure of theoriginal aluminum sodium silicate is new and the primary object of thisinvention.

' Thisrinvention is particularly adaptable to bentonite, a colloid claydescribed 1n our co-pending application, Serial No. 669,306, filed Oct.18, 1923. The so-called bentonite of commerce is not a pure sodiumaluminum silicate but carries the above mentioned impurities which havereplaced a portion of the Application filed January 21, 1924. Serial No.687,655.

dition of'alumina base to the clay. The.

alumina base may be added to the clay either .by addition to the wet'mineral in 'dry form alumina or alkali of the true bentonite. The i becompletely of aluminum sulphate and caustic soda, or in solution as willbe later described.

One form of ourprocess of preparing bentomte-like' minerals for use asawater softening agent will now be described in detail,

a) Grinding and sizing. The natural mineral is ground and screened tosize de-- I sired for use in the tanks of the water softening mechanism.

(b) Calcining. The sized mineral is now calcined to a temperaturebetween 800 and 950 degrees 0., until a test by pyrometer'or to sinter.l

(c) "Activating. The calcined mineral is soaked or steeped in a solutionof sodium Seger cones shows that it has commenced aluminate containingfive per cent of a solution'of common salt (NaCl). This solution shouldcontain the least possible amount of water to reduce the time requiredfor drying out the excess. The preferred meth- 0d of preparing thissolution willbe later described. a

(d) Drying. The activated mineral is now sub it is ready for use.

ected' to a heat of approximately 105 C. toevaporat'e out the excesswater and The resulting product is a stable y aluminum silicate, theimpurities (lime,

magnesium, etc.) in the chemical-combine tion having been replaced byaluminum and sodiumhydroxides. These impurities are now present assoluble chlorides and sulphates which are washed from the product,either in the factory or more preferably, after it is in place in thewater softener tanks. v

The solution used in step (c) is best made by adding to aconcentratedsolution of technical aluminum sulphate, such as used on 21- large scaleby water works as a coa letting and settling agent, a concentrated s0ution of caustic soda, which at first precipitates the alumina ashydroxide, but on further addition rte-dissolves the alumina formingsoluble sodium aluminate. To this solution is natural mineral.

by the mineral, leaving but small excess to be evaporated out.

When the dry aluminum sulphate and caustic are added to the wet mineral,the above reactions all take place within the min eral itself. The useof the NaCl solution may be dispensed with, without impairing theefiectiveness of the process, it being used only to reduce the amount ofcaustic necessary and thereby reduce the cost of the process.

The use-of the words clay and mineral herein is to designate anybentonite-like, so called alumino-silicat-e which can be reconverted,either entirely or partially, into a stable sodium aluminum silicate.

If desired, the salt and caustic soda may be added to themineral beforethe calcination step and the aluminum sulphate added after thecalcination.

While we have described in some detail one perferred method of carryingout our process, together with thetheories which we believe to explainthe success of the same,

it is understood that our invention is not limited to the preciseprocedure described nor is it dependent upon the accuracy of thetheories which we have advanced. On the contrary, our invention is notto be re arded as limited except in so far as such 'mitations areincluded within the terms of the accompanying claims, in which, it isour intention to claim'all novelt inherent in our invention as broadlyas is permissible in View of-the prior art.

Having thus described our invention, what we claim and desire to secureby Letters Patent is 1. A process of treating altered aluminosilicateminerals of the bentonite variety which are deficient in alumina for useas a water softening agent, comprising the add ing thereto of a compoundwhich will introduce aluminum hydroxide therein so as to replace thedeficienc 2. A process of treating the altered alumino-silicate clays ofthe bentonite variety which are deficient in alumina, comprising theadding thereto of a compound ihich will introduce alumina base to the cay.

3. A process of treating alumino-silicate minerals, of the bentonitevariety, for use as a water softenin agent, comprising, grinding andsizing t e mineral, calcining the sized mineral; treating-the calcinedmin- 1,57o,0oc

eral with a soluble aluminum compound and drying out the excessmoisture.

a. A process of treating the aluminq-silicate minerals, of the bentonitevariety, for use as a water softening agent, comprising, grinding andsizing the mineral, calcining the sized mineral; treating the calcinedmineral with sodium aluminate and drying out the excess moisture.

5. A process of treating the altered alumino-silicate minerals of thebentonite variety in which a part of the alumina content has beenreplaced by impurities for use as a water softening agent, comprising,grinding and sizing the mineral, calcining the sized mineral atsintcring ten'iperature and treating the calcined product to formaluminum hydroxide so as to replace the deficient alumina.

6. A process of treating the aluminosilicate minerals, of the bentonitevariety, for use as a water softening agent, comprising, grinding andsizing the mineral, calcining the sized mineral, treating the calcinedmineral with aluminum sulphate and caustic soda and drying the treatedmineral.

7. A process of treating the alumino-silicate minerals for use as awater softening agent, comprising, calcining the minera treating thecalcined mineral with aluminum sulphate, caustic soda, and sodiumchloride, and drying the treated mineral.

8. In a process for treating the aluminosilicate minerals for use insoftenin water, the step which comprises treating t e mineral withsodium aluminate.

9. In a rocess for treating the altered alumino-sihcate minerals whichare deficient in alumina for use as a water softener, the step whichcomprises the addition of a compound which will add aluminum oxide tothe mineral. I

10. In a process for treating the altered alumino-silicate mineralswhich are deficient in alumina for use in softening water, the stepwhich comprises treating the mineral to form aluminum hydroxide.

11. In a process for treating the altered alumino-silicate minerals ofthe bentonite variety which are deficient in alumina and alkali for usein softening water, the step which consists in adding to the mineralaluminum sulphate and caustic soda.

12. In a process for treating altered bentonite which is deficient inalumina and alkali for use as a water softening agent, the step whichconsists in adding to the mineral the combination of water, aluminumsulphate, caustic soda, and sodium chloride.

In testimony whereof, we affix our signatures.

HERMAN REINBOLD. HUGO REINBOLD.

